The VTC actuator is composed of the vane, the lock pin, the pin spring, and the housing with the timing gear. It is installed at the end of the camshaft.
When the VTC actuator vane rotates to advance or retard position, the intake camshaft timing is changed.
When the engine stops, the vane is locked in the initial position by the lock pin so that the engine will start smoothly. After the engine starts, the vane turns freely because the lock pin is pushed back against the spring tension by oil pressure.

To control the camshaft angle continuously, the VTC oil control solenoid valve controls oil pressure to the advance chamber/retard chamber of the VTC actuator according to a signal from the PCM.
The solenoid valve has a strainer that to avoid foreign material contamination.

When the advance chamber is charged with pressured oil from the VTC oil control solenoid valve, the camshaft rotates to the advanced side.
In case of the oil non-pressurized state (engine is stopped), VTC actuator B is locked in the most advanced position by the return spring and the lock pin.

When the retard chamber is charged with pressured oil from the VTC oil control solenoid valve, the camshaft rotates to the retarded side.
In case of the oil non-pressurized state (engine is stopped), VTC actuator A is locked in the most retarded position by the lock pin.